.TH std::chrono::time_point::time_since_epoch 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::chrono::time_point::time_since_epoch \- std::chrono::time_point::time_since_epoch

.SH Synopsis
   duration time_since_epoch() const;  \fI(since C++11)\fP
                                       (constexpr since C++14)

   Returns a duration representing the amount of time between *this and the clock's
   epoch.

.SH Parameters

   \fI(none)\fP

.SH Return value

   The amount of time between this time_point and the clock's epoch.

.SH Example


// Run this code

 #include <chrono>
 #include <ctime>
 #include <iostream>

 int main()
 {
     const auto p0 = std::chrono::time_point<std::chrono::system_clock>{};
     const auto p1 = std::chrono::system_clock::now();
     const auto p2 = p1 - std::chrono::hours(24);

     std::time_t epoch_time = std::chrono::system_clock::to_time_t(p0);
     std::cout << "epoch: " << std::ctime(&epoch_time);
     std::time_t today_time = std::chrono::system_clock::to_time_t(p1);
     std::cout << "today: " << std::ctime(&today_time);

     std::cout << "hours since epoch: "
               << std::chrono::duration_cast<std::chrono::hours>(
                      p1.time_since_epoch()).count()
               << '\\n';
     std::cout << "yesterday, hours since epoch: "
               << std::chrono::duration_cast<std::chrono::hours>(
                      p2.time_since_epoch()).count()
               << '\\n';
 }

.SH Possible output:

 epoch: Thu Jan  1 00:00:00 1970
 today: Fri Jun 30 10:44:11 2017
 hours since epoch: 416338
 yesterday, hours since epoch: 416314
